Edible dispersions comprising oil and structuring agent are well known in the art and include for example shortenings comprising a fat phase and water in oil spreads like margarine comprising a fat phase and an aqueous phase.
The fat phase of margarine and similar edible fat continuous spreads is often a mixture of liquid oil (i.e. fat that is liquid at ambient temperature) and fat which is solid at ambient temperatures. The solid fat, also called structuring fat or hardstock fat, serves to structure the fat phase (being the case for example in a shortening as well as in a water in oil emulsion) and helps to stabilize the aqueous phase, if present, by forming a fat crystal network. For a margarine or spread, ideally the structuring fat has such properties that it melts or dissolves at mouth temperature. Otherwise the product may have a heavy and/or waxy mouthfeel.
Important aspects of a fat continuous spread like for example margarine and low fat spread, the low fat spread usually comprising from 10 to 40 wt % fat on total composition, are for example hardness, spreadibility, the amount of water released after spreading (i.e. free water) and ability to withstand temperature cycling. Temperature cycling means that the product is subjected to low and high temperatures (e.g. when the consumer takes the product out of the refrigerator and leaves it for some time at the table to use it). This may have a negative influence on the structure of the spread (like for example destabilization of the emulsion or oil-exudation).
Generally edible fat continuous food products like for example margarines and similar edible fat continuous spreads are prepared according to known processes that encompass the following steps:    1. Mixing of the liquid oil, the structuring fat and if present the aqueous phase at a temperature at which the structuring fat is definitely liquid;    2. cooling of the mixture under high shear to induce crystallization of the structuring fat to create an emulsion;    3. formation of a fat crystal network to stabilize the resulting emulsion and give the product some degree of firmness;    4. modification of the crystal network to produce the desired firmness, confer plasticity and reduce the water droplet size.
These steps are usually conducted in a process that involves apparatus that allow heating, cooling and mechanical working of the ingredients, such as the churn process or the votator process. The churn process and the votator process are described in the Ullmans Encyclopedia, Fifth Edition, Volume A 16, pages 156-158.
A disadvantage of these processes is that the complete composition (including the liquid oil, structuring fat and if present the aqueous phase) is subjected to a heating step and a cooling step. This requires a lot of energy. For a spread comprising for example 6 wt % structuring fat the whole composition (100 wt %) has to be heated and cooled.
Another disadvantage of the known processes is that the choice of fats that can practically be used as structuring agent is rather limited. If the melting point of the structuring agent is too high the melting properties in the mouth are unsatisfactory. If on the other hand, the melting point is too low, the emulsion stability will be negatively affected. Moreover the amount of saturated fatty acids (SAFA) in the structuring agent is usually relatively high. Also trans fatty acid may be present. Some experts have called for reductions in these fatty acids to improve cardiovascular health.
Some consumers prefer spreads that have a low energy density (for example products that are low in total fat) and/or are low in SAFA but still have a good nutritional profile (by providing for example essential fatty acids like omega-3 and omega-6).
A further disadvantage of the known processes is that the product may deteriorate due to the changes in temperature caused by the heating and cooling step.
Alternative processes have been described wherein the structuring fat is added as fat powder (i.e. crystallized fat) thereby eliminating the need to heat the whole composition to above the melting temperature of the structuring fat.
EP 1 651 338 A1 discloses a process for the preparation of an edible dispersion like for example margarine, wherein the dispersion is formed by mixing oil, solid structuring agent particles and an aqueous phase and/or solid phase. The solid structuring agent particles have a microporous structure of submicron size particles. Said particles can be prepared using a micronisation process. The particles have a microporous structure which may result in low bulk density powders. Such powders are not always convenient to handle in a production environment.
EP 1 285 584 A2 describes a method of producing a food product formulation having plasticity or firmness comprising or consisting of a uniform dispersion of crystalline solid fat in an oil phase comprising bringing the solid fat phase with a minimal amount of the oil phase in a liquid state to a cooling device employing cryogenic spray crystallization and therein cooling the molten fat using a cryogenic medium to effect fat crystallization as quickly as possible. No details are given regarding the process conditions of the cryogenic spray crystallization.
Food Ingredients and Analysis International Vol. 23 No. 4 pages 29-30 (2001) describes powdered fats based on cryogenic technology that can be used for example in pourable margarines and different types of soft fat spreads. It is however mentioned that powdered fats may be used in combination with liquid oil, but for optimal performance these products need a specially designed fat composition which is crystallized from the melt. This will give the best structure of the crystal fraction, and allows a stabilizing network of crystals to be formed during cooling.
EP 0 393 963 A2 describes a method for cryogenic crystallization of fat comprising introducing a fine downwardly directed spray of atomized liquid fat into the upper portion of a mixing chamber while directing a plurality of fine jets of cryogenic liquid against the downward spray of liquid fat droplets. The fat is sprayed at a pressure of about 2.7 bar. No further details are given regarding the process conditions of the cryogenic spray crystallization.
EP 2 181 604 A1 describes a method of preparing a fat powder suitable for structuring agent e.g. in margarines wherein a structuring agent comprising composition is sprayed from a pressurized container into an environment, thereby expanded and then treated with a coolant. The pressure difference is 4-40 MPs.